Background To evaluate the visual and anatomic outcomes after systemic steroid treatment in non-arteritic anterior ischemic optic neuropathy (NAION). Methods Ten eyes from ten patients diagnosed with NAION and treated during the acute phase with 80 mg daily, tapering-down dose of corticosteroids were compared with a non-contemporary cohort of 27 patients that received no treatment. The visual outcomes of treated and untreated group were compared. Patients underwent complete ophthalmic examination including determination of Snellen visual acuity (VA), visual fields (VFs) (standard automated perimetry, Swedish Interactive Testing Algorithm 24–2 strategy), and optical coherence tomography (OCT) scanning of the optic nerve head at diagnosis, 6–8 weeks and 6 months after presentation. Results No statistical differences were found between steroid-treated and untreated NAION for the median change in VA (Mann–Whitney P =  0.28), median change in VF mean deviation (MD) and median change in VF pattern standard deviation (PSD) (Mann–Whitney P =  0.213 and P =  0.07 respectively). Statistical analysis showed no differences when comparing average RNFL loss ( P  = 0.871) and RNFL loss for superior, nasal, inferior and temporal optic disc quadrants between both groups. Complications occurred in three of the ten treated patients (30%); in one of them, steroid therapy had to be discontinued. Another two patients developed a NAION in their fellow eye after 2 and 3 months while on low-dose prednisone. No complications developed in the control group. The study was interrupted early due to a significantly higher rate of complications observed in the treated group ( P =  0.002) Conclusion High-dose systemic steroid treatment did not show any beneficial effect in visual and anatomic outcomes when given during the acute phase of NAION. Furthermore, it caused serious complications in a third of the patients treated.